Multiple-section molding press

ABSTRACT

A multiple-section molding press having molding press sections arranged in aligned vertical and horizontal rows. Each section has a fluid pressure-operated platen. A vertically movable horizontal elevator platform member is adapted to receive box molds from a conveyor, and the box molds can be moved along the platform member so as to be manually positioned adjacent any of the vertical rows of press sections. A bank of illuminated control switches is provided for the sections. The elevator platform is provided with pushers and ejection devices aligned with the respective vertical rows. Automatic vertical positioning circuits are provided for the platform member, as well as press cycling circuits, operating in response to the actuation of a selected illuminated control switch to place a mold box at the level corresponding to the selected illuminated switch. The associated pusher automatically moves the mold box into press position and simultaneously ejects a previously compressed mold box therefrom onto the discharge side of the platform so that it is engaged by the associated ejection device. The platform returns to conveyor level. A respective timer is provided to control the action of each of the press sections and to indicate completion of a press cycle.

[ 1 Sept. 18, 1973 MULTIPLE-SECTION MOLDING PRESS [75] Inventor: ClaudeT. Tyler, Warsaw, Ind.

[73] Assignee: Tyler Machinery Co., Inc., Warsaw,

, Ind.

22 Filed: Feb. 4, 1972 [21] Appl. No.: 223,506

[52] US. Cl. 425/145, 425/169, 425/156,

7 425/234, 425/33s [51] Int. Cl..;.... 1130b 7/02, 1330b 15/16, 329g7/02 [58] Field of Search 425/333, 339, 340, 425/341, 455, 394, 397,234, 145

[56] References Cited UNITED STATES PATENTS 3,157,910 11/1964 Schlipphak425/254 3,206,800 9/1965 Muller 425/339 X 3,611,482 10/1971 l-lutz425/338 X 2,543,582 2/1951 Lyijynen 425/339 X 2,831,213 4/1958 Klarmannct al 425/339 3,170,189 2/1965 l-lutter 425/339 3,368,242 2/1968Loewenfeld et al. 425/339 X 3,517,610 6/1970 Siempelkamp.. 425/341 X3,551,944 l/1971 Muller 425/340 Primary Examiner- J. Howard Flint, Jr.Attorney-Hyman Berman et al.

[ I ABSTRACT A multiple-section molding press having molding presssections arranged in aligned vertical and horizontal rows. Each sectionhas a fluid pressure-operated platen. A vertically movable horizontalelevator platform member is adapted to receive box molds from aconveyonand the box molds can be moved along the platform member so asto be manually positioned adjacent any of the vertical rows of presssections. A brink of illuminated control switches is provided for thesections. The-elevator platform is provided with 'pushers and ejectiondevices aligned with the respective vertical rows. Automatic verticalpositioning circuits are provided for the platform member, as well aspress cycling circuits, operating in response to the actuation of aselected illuminated control switch to place a mold box at the levelcorresponding to the selected illuminated switch. The associated pusherautomatically moves the mold box into press'position and simultaneouslyejects a previously compressed mold box therefrom onto the dischargeside of the platform so that it is engaged by the associated ejectiondevice. The platform returns to conveyor level. A respective timer isprovided to control the action of each of the press sections and toindicate completion of a press cycle.

O00 0 '000 0000 000 000 00 0000 Dog 0000 PATENTED SEN 8 I973 SHEET 1 0F8 PATENTEU SEP 1 8 I975 SHEEI 8 [1F 8 PATENIED SEPI 81973 SHEEI 7 BF 8.m m WUx-Q pacity, and which ishighly automated.

, I I MULTIPLE-SEGTION MOLDING PRESS This invention relates to pressuremolding devices, and more particularly to improvements in multipleplatenpresses for use in molding plastic parts.

A main object of the invention is to provide a novel and improvedmultiple-section platen press which is relatively simple inconstruction, which has a high ca- A further object of the invention isto provide an improved multiple-section platen press for making plasticfoam castings and for makingvarious other types of plastic castingshaving sizable face areas relative to ing' height.

A still further object of the invention is to provide an improvedmultiple-section platen press having elevator means for transferringmold boxes to the proper height to be inserted beneath an availableplaten, the elevator arrangement being such that it returnsautomatically to FIG. d is a fragmentary transverse verticalcrosssectional view taken substantially on the line d-d of FIG. 2,showing the rear, or discharge, side of the multiple-section moldingpress of FIG. I;

FIG.'5 is an enlarged fragmentary horizontal cross sectional view takensubstantially on the line E-fi of FIG; 2;

FIG. 6 is a vertical cross-sectional view taken substantially on theline 6-45 of FIG. 5;

FIG. 7 is a partial schematic diagram showing the fluid circuit of oneof the press sections of the multiplesection molding press of FIG. I;and

FIGS. ha and 8b together constitute an electrical wiring diagram showingthe electrical connections of the electrical components associated withuppermost, left end press section of the multiple-section molding pressof FIG. I, and typifying the electrical circuits employed for all of themolding press sections of the assembly.

The rapidly growing field of foam castings as replace- 0 ments for manywood parts or parts made of other realtively expensive materials callsfor suitable apparatus for retaining the foam securely while thechemicallygenerated heat therein expands the foam to till a mold box. Ifthe casting has a substantial face area, relative 5 to depth, thisretention can often best be done by employing a platen press. A platenpress is very satisfacpliedsubstantially uniformly over the platensurface.

normal conveyor height. so that mold boxes can be supplied from a feedconveyor by simply rolling the mold boxes onto the elevator platformwhere the mold boxes can be properly positioned for feeding beneathavailable platens, and whereby processed mold boxes can be convenientlymoved onto a receiving conveyor for further processing.

A still further object of the invention is, to provide an improvedmultiple-section molding press employing molding press sections of thepressure-vacuum pod type, the sections being arranged in alignedvertical and horizontal rows, and automatic elevator means beingprovided to automatically place a mold box at the proper levelcorresponding to an available molding press section, the elevator memberautomatically returning to normal conveyor height, thereby greatlyfaciliting the supplyof mold boxes to the apparatus and the removal ofcompressed mold boxes therefrom, the apparatus providing a considerablesaving in labor in the handling of the mold boxes and providing arelatively high capacity for processing mold boxes therethrough becauseof its time-economizing features.

Further objects of the invention will become apparent from the followingdescription and claims, and from the accompanying drawings, wherein:

F101 is a perspective view showing a typical multiple-section moldingpress assembly constructed in accordance with the present invention;

FIG. 2 is an enlarged frgmentary front elevational view, partly invertical cross-section, of the right side portion ofthernultiple-section molding press assembly shown in FIG. 1;

FIG. 3 is afragmentary transverse vertical cross-- sectional view, takensubstantially on the line 3-3 of FIG. 2, showing the front, orreceiving, side of the multiple-section molding press;

At the present time, it appears that a pressure of -20 to 30 lbs. persq. inch on'the mold box is adequate to resist the foaming action.-

Wherethere is a requirement for a substantial vol- ,ume of production,a-corresponding large number of platen presses is required, and thesemust be employed in an organized manner in view of the fact that pouredfoam must be placed under pressure with in about 1 min.,' the pouringtime being only a few seconds, and whereas the curing time underpreddure is of the order of several minutes. A prime purpose of thepresent invention is to provide an apparatus embodying a substantialnumber of individual platen press assemblies embodied in a compactassemblage with provision 5 being made to take care of the necessaytimingrequirements of properly pouring, compressing and curing foamcastings of the type above mentioned and insuring efficient utilizationof the large number of platen press assemblies provided in theapparatus.

A unique characteristic of the present invention is the provision ofvertically stacked individual platen press assemblies with an automaticelevator system to move mold boxes to the proper level corresponding toavailable platen press assemblies. Another unique feature of the presentinvention is the alternate use of pressure and vacuum in the pressurepods of the'platen press assemblies. In each platen press assembly,vacuum is employed to raise the associated platen to thus permit instantmovement of a mold box into the press assembly for subsequentcompression by the platen. This feature enables the apparatus to occupya minimum amount of vertical space, which is of considerable importancebecause a substantial number of rows are 5 required to provide thenecessary production capacity and this number is limited by ceilingheight factors.

Another unique feature of the present invention'is the location of thepressure. pod elements the framework immediately above the platen. Thisfeature provides a substantial reduction in vertical heightrequirements, as well as allowing suitable distribution of load carryingmembers within the framework of the apparatus so as to provide mostefficient utilization of the framing and to minimize local deflectionsof its members.

Still another important and novel feature of the present invention isthe provision of an elevator system which always returns automaticallyto the same elevation; namely, on the in feed side to the elevationcorresponding to that of the input conveyor, thus enabling an operatorto simply roll a newly filled mold box to the proper position, asindicated by a signal lamp on the control panel, whereas on the outputside of the machine, the elevator automatically returns to the properelevation which corresponds to that of the receiving conveyor on which amold box containing a cured casting can be rolled onward in the plantfor de-molding and further processing. A still further interesting andunique feature of the apparatus of the present invention is the abilityof easily enlarging the machine so as to add additional platen pressassemblies, add the required longer elevator screws, and easilyreassemble the machine with its substantially increased productioncapacity.

As will be presently described, the use of the elevator member providesconsiderable economy in time and reduction in required physical labor.The elevator also is provided with powered pusher mechanisms which pushthe mold boxes into press positions in their associated platen pressassemblies while at the same time starting finished molds out of theassemblies on the opposite side. The elevator portion of the apparatusis likewise provided with powered rollers which engage the emerging moldboxes and carry them out the remaining necessary distance on the exitside of the assembly. An out feed operator is then able to roll the moldboxes along the elevator in a longitudinal direction; namely, at rightangles to the movement of the mold boxes into and out of the platenpress assemblies. As above mentioned, the elevator automatically returnsits home" position. At this home elevation its surface registers withthe plant conveyor and pouring station elevations. Also, in this home"position the elevator registers with the elevation of one of thehorizontal rows of platen press assemblies in the machine.

Referring to the drawings, generally designates an improvedmultiple-section molding press constructed in accordance with thepresent invention. The assembly 20 is provided with an upstanding rigidframework having a pair of transversely extending supporting base anglebars 21,21. Perpendicularly secured to the bottom angle bars 21,21 is arectangular box-shaped bottom frame structure comprising front and rearlongitudinally extending vertical plates 22 connected by transverselyextending vertical end plates 23 rigidly secured thereto. Rigidlysecured on the top edges of the plates 22 and 23 is a horizontal supportplate 24, employed as the mold box supporting plate for the lowermosthorizontal row of platen press assemblies, presently to be described.The frame structure is provided at its top portion with a similarlongitudinally-extending box-like structure comprising front and rearlongitudinally extending vertical plate members 26 connected at theirends by transversely extending vertical plate members g7, A pair ofvertical frame bars 28,28 are rigidly connected at the top and bottomends respectively to the transverse plate members 27 and 23 at theopposite ends of the main supporting frame. A horizontal top cover plate29 is secured rigidly to the top edges of the plates 26 and 27 at thetop portion of the main supporting frame. Depending bracket members 30are rigidly secured to the opposite end portions of the bottom platemembers 22 and are secured in the transverse angle bars 21.

The main supporting frame also includes a plurality of uniformly spacedrectangular box-like platforms similar to that defined by the top platemembers 26, 27 and 29, said additional platforms being uniformly spacedbetween the top structure defined by said members 26, 27 and 29 and thebottom box-like rectangular fixed structure defined by the plate members22, 23 and 24. Thus, the intermediate fixed horizontally extendingplatform structures comprise longitudinally extending front and rearvertical plate members 26 and transverse vertical end plate members 27,longitudinally extending horizontal plate members 24 being rigidlysecured to the top edges of the plate members 26 and 27. The tophorizontally extending plate member 29 is similar to the plate members24 except that it is provided with upstanding bearing brackets 31rotatably supporting a horizontal shaft 32 for a purpose presently to bedescribed.

In the typical embodiment illustrated in the drawing and describedherein, there are five box-like structures spaced above the bottom boxstructure, defining five horizontal press spaces. The box structuresabove each of said spaces are further provided with internallongitudinally extending rectangular central tubular members 33 rigidlysecured at their top walls to the horizontal plate members 29 or 24 andrigidly secured at their opposite ends to the transverse plate members27. Rigidly secured transversely between the front and rear verticalplate members 26 of each of the fixed box-like structures and thevertical front and rear walls of the tubular member 33 are transverselyextending plate members 34 spaced to define respective rectangularenclosures for bellows-like pressure pods 35 secured to horizontalplaten ssemblies 36 presently to be described. In the typical embodimentdescribed herein, four sets of enclosures are defined for eachhorizontal fixed frame portion and the bellows-like pod elements arearranged in pairs located respectively on opposite sides of thelongitudinal tubular frame member 33 of each horizontal frame section,as shown in FIGS. 5 and 6. Each bellows-like pod member 35 is secured toand depends from a pair of spaced transversely extending angle bars38,38 rigidly secured between the vertical walls of the centralhorizontal tubular frame member 33 and the longitudinally extendingouter vertical plate members 26, as shown in FIGS. 5 and 6. Each platenmember 36 is secured to and moved by the bottom walls of a pair oftransversely aligned bellows-like pod members 35. As shown in FIGS. 2and 6, the horizontal platen members 36 are generally rectangular inshape and are of hollow construction. The platen members are provided attheir comers with upstanding vertical plunger elements 39 which slidablyengage in depending vertical guide cylinders 40 rigidly secured to anddepending from the horizontal top plate members 24 or 29, so as toaccurately guide the horizontal platen members 36 for vertical movement.

The pressure pods 35 are of conventional construction, and may besimilar to Airstroke Actuators manufactured by Firestone IndustrialRubber Products Company, Noblesville, Indiana.

The platen members 36 are lowered and raised by the respective expansionand contraction of their associated pressure pod members 35. Each'set ofpressure pod-members35,35', associated with a particular platen member36,-is'connected by a respective conduit 41 to a supply conduit 42 (seeFIG. 7), the conduits 41 extending through the central horizontallongitudinal hollow member 33. Conduit 42 may be communicativelyconnected to either a vacuum line 45 or a compressed air line 46depending upon the condition of an associated main control valve 44which is of the two-position type and which is connected between thepair of pods 35 and the lines 45 and 46 in the manner diagrammaticallyillustrated in FIG. 7. Thus, the main control valve 44 associated witheach pair of bellows-like pod elements 35 is normally biased to aposition such as that diagrammatically illustrated in FIG. 7 wherein theconduit 42 is connected through the valve and a conduit 47 to the vacuumline 45. Valve 44 is of the pressureactuated type, and each valve 44 iscontrolled by 'a respective pilot valve 48 of the solenoid type. Thus,in the normally, deactivated, condition of main valve 44 the line 42 isconnected to the vacuum line 47, as above mentioned. When the valve 44is actuated the line 42 becomes connected to a conduit 49 which is inturn connected to the compressed air line 46. This occurs when thesolenoid of the associated pilot valve 48 is energized, therebyconnecting the conduit 50, shown in FIG. 7, to the pressure conduit 46.Thus, in a normal condition of the parts, the bellows members 35,35 areconnected to the vacuum line 45and are contracted, causing the platenmember 36 to be elevated. When the solenoid of the associated pilotvalve 45 becomes energized, compressed air is admitted to the associatedmain valve 44 through the line 50, and the supply line 42 for the pods35,35 becomes connected to the compressed air supply conduit 49 by theaction of valve 44, causing the pods 35,35 to expand and to exertdownward force on the associated platen member 36, causing said platento move downwardly through a mold box-compressing stroke.

From the above, it will be apparent that a pilot valve 48 is providedfor each of the twenty platens 36 of the typical assembly illustrated inthe drawingsand described herein. The diagram of FIG. 7. illustrates themanner in which the pods members 35,35 of the extreme uppermsot leftplaten member are connected to the main compressed air. supply line 46and vacuum line 45, and in this typical instance, the solenoid for theassociated pilot valve 48 is identified as 81A. The pneu maticallyactuated components, shown in the dotted rectangle in FIG. 7 representthose required for eachv platen member 36, and it will understood thatcorresponding' assemblies are provided for each of the other nineteenplaten members of the illustrated apparatus.

As shown in FIG. 7, vacuum is maintained in line 45 by a vacuum pump 52driven by an electric motor M3. A vacuum sensing switch SW6, presentlyto be described, is connected to the vacuum line 45.

Elevator screws 53 are vertically joumaled at the respective corners ofthe frame structure thus far described. Thus, the lower ends of thescrews are rotatably supported in bearing brackets 54 rigidly securedmotor M1 of the reversible type. The motor M1 is suitto the lowerportion of the plate members 23 and the upper portions of the screws arerotatably supported in sleeved bearing brackets 55 secured to thetransverse top end plate 27. The top ends of the screws 53 have bevelledgears 56 secured thereto, said bevelled gears being meshingly engaged bybevelled gears 57 provided on the ends of the shaft 32. Mounted on theintermediate portion of shaft 32 is a relatively large sprocket wheel 53which is drivingly coupled by a sprocket chain to a smaller sprocketwheel on the shaft of a drive ably mounted on horizontal top plate 29.Motor MI is operated in a conventional manner and the forward andreverse operation thereof occurs in response to en ergizationrespectively of coils MlF and MIR illustrated schematically in FIG. 8B.

It will be understood that a drive shaft 32 is provided at each side ofthe machine; namely, on the front side and on the rear side, and thateach shaft 32 is coupled ina similar manner to the respective elevatorscrews 53,53 at its side of the machine. The rear driving shaft 32 isprovided with a sprocket wheel 58 and is coupled by .a sprocket chain toa smaller'sprocket on the shaft of the motor M1 in the same manner asabove de scribed for the front elevator screws 53. Thus, when the motorM1 is energized, the screws 53 rotate simultaneously in the samedirection, either forward or reverse, to provide elevation or loweringof the elevator assembly presently to be described.

The elevator assembly is designated generally at 60 and comprises agenerally rectangular framework having transversely extending end platemembers 61 whose front ends are rigidly connected by a longitudinallyextending vertical plate member 62. The transversely extending end platemembers 61 are located outwardly adjacent the vertical frame bars 28,23at each end of the main frame of the machine, and are provided withinternally threaded vertical sleeve members 64 rigidly secured to theplate members 61 and threadedly engaged with the elevator screws 53. Alongitudinally extending angle bar 65 is employed to rigidly connect thetransversely extending vertical end plates 61 at the lower marginalportions of said transversely extending plates at the front portion ofthe elevator assembly. 60, and a longitudinally extending channel bar 66is likewise employed to connect the lower portions of the plates 61adjacent the stationary main frame of the machine, as shown in FIG. 3,to rigidify this portion of the elevator member. The rear portions ofthe transversely extending end plates 61 are rigidly connected by a pairof longitudinally extending spaced channel bars 69 and means forlimiting rearward movement of mold boxes ejected rearwardly from theplaten press assemblies. as shown in dotted view in FIG. 4. i

As shown in FIG. 3, alongitudinally extending channel bar 74 is securedvertically between the end plates 61 adjacent the vertical plane of thefront wall plates 26 of the pod enclosures on the main chine.

As shown in FIG. 2, the adjacent transverse edges of elevator top plates27 at the front portion of the elevator assembly 60 are spaced apart todefine guide ways substantially centered with respect to the verticalrows of platen members 36. Rigidly secured in these guide ways areparallel pairs of transversely extending guide rods 75,75, the frontends of the rods being secured to brackets 76 rigidly secured to theupper marginal portion of front plate 62, and the rearends of the guiderods 75 being secured to supporting blocks 77 which are in turn rigidlysecured to the top flange of the longitudinally extending channel-shapedframe bar 74. Slidably mounted on the respective pairs of guide bars75,75 are pusher carriage blocks 77 having horizontal flat bar members78 rigidly secured to and projecting rightwardly therefrom, as viewed inFIG. 3. Rigidly secured on the rightward ends of the bar members 78, asviewed in FIG. 3, are clamping blocks 79 having horizontal slots inwhich are adjustably mounted horizontally extending pusher bars 80 whichextend parallel to the guide rods 75 and which are provided at theirrearward ends (right ends as viewed in FIG. 3) with mold box-engaginglongitudinally extending vertical pusher plates 81, the bars 80 beingadjustably clamped in the blocks 79 by the provision of manuallyoperable clamping screw members 82 thread-edly engaged through the topwalls of the slots in the blocks 79.

The carriage blocks 77 are provided with pairs of depending spacedbracket elemetns 83 which receive therebetween and are secured to thetop runs of respective endless sprocket chains 84 which extendtransversely and which are supported on respective idler sprockets 85and 86 secured on longitudinal shafts 87 and 88 journaled between theend plates 61, the shaft 87 being located adjacent the front longtudinalwall plate 62 and the shaft 88 being located adjacentthe longitudinallyextending channel bar 74, as is clearly shown in FIG. 3. A pusher motorM2 provided with a reducing gear assembly 90 is mounted on thelongitudinally extending channel bar 66 and has an output sprocket 89drivingly coupled by a sprocket chain 91 to a sprocket 92 mounted on theshaft 88, whereby the motor M2, which is of the reversible type, isdrivingly coupled to the carriage blocks 77 of the respectiveabove-described pusher assemblies.

As shown in FIG. 4, a longitudinally extending shaft 93 is journaledbetween the upper portions of the plates 61 and secured on shaft 93 area plurality of rollers 94, shaft 93 being located rearwardly adjacentthe vertical plane of the rear wall plates 26 of the platen podenclosures. The rollers 94 are located so that their top peripheralsurface portions are substantially coplaner with the top plane of theupstanding mold conveyor assemblies 68, as is shown in FIG. 4. Shaft 93is drivingly coupled to shaft 88 by a sprocket chain 95 which ismeshingly engaged respectively with a drive sprocket 96 secured on theend of shaft 88 and a driven sprocket 97 secured on the end of shaft 93.Thus, the rollers 94 are simultaneously rotated in a clockwisedirection, as viewed in FIG. .4, as the pusher carriage blocks 77 moverightwardly, as viewed in FIG. 3. Therefore, as a mold box, shown at 98is pushed rightwardly by a pusher pad 81, as viewed in FIG. 3, itengages a previously processed mold box restingon a horizontalsupporting plate 24 and pushes said previously processed frame of themamold box rightwardly as viewed in FIG. 3 and as viewed in FIG. 4, sothat it is engaged by a roller element 94 and propelled furtherrightwardly onto the spherical ball conveyor elements 68, its rightwardmovement being limited by it engagement with the stop bar 73, abovedescribed.

As shown in FIG. 1, the platen members 36 are constrained to movevertically by the provision of vertical guide means comprisingupstanding vertically projecting guide bars 99 rigidly secured to themid-portions of their front edges, said guide bars 99 being slidablyreceived between and being contained between cooperating pairs ofinwardly flanged vertical guide rails 100,100 vertically secured to theoutside surfaces of the longitudinally extending wall plates 26 of thepod enclosures. Cooperating guide bars 99 and pairs of guide rails 100are provided both on the front side and the rear side of each podenclosure so that the associated platen member 36 is positivelycontrained to move vertically. This assures that parallelism will bemaintained between the platen members 36 and the cooperating subjacentfixed supporting plate members 24.

In a generalized mode of operation of the machine, the elevator member60 is normally positioned at a level so that it is flush with a moldbox-feeding conveyor leading from a station at which the molds arefilled. A filled mold box from said station is manually rolled onto theelevator 60 from said station, being supported on the transfer ballassemblies 68 and is manually moved into alignment with a vertical rowof platen press assemblies containing a platen press assembly which isready to be refilled. As will be presently described, an illuminatedindicator on a control panel 101 informs the operator of the correctlocation in which to place the mold box to be processed. The operatorthen actuates'a suitable control switch to bring the elevator member 60to the proper level corresponding to the available platen press unit,after which the associated platen member 36 is elevated and the pushermechanism is activated to push the new mold box into the platen pressposition and simultaneously cause the previously processed mold box tobe ejected and moved to the rear portion of the elevator assembly in themanner above described; namely, by the action of a roller 94. The pushermember 77 is retracted and positive pressure is applied to the podassembly containing the new mold box, whereby to apply molding pressurethereto, and the elevator member 60 is returned to its home position,flush with a receiving conveyor on which the previously processed moldbox is moved, and at which the elevator is in the proper position toreceive the next mold box to be processed from the feeder conveyor.

The above described general cycle of operation may be accomplishedeither by manual control of the electrical circuits associated with therespective operating motors, or by an automatic control circuit,presently to be described.

Thus, referring to FIGS. 8a and 8b, the apparatus is provided with amain supply transformer 102 having input terminals L1 and L2 which maybe suitably connected to a source of energizing alternating current. Thesecondary winding 103 of transformer 102 has one terminal connectedthrough series-connected normally closed protective motor overloadswitches XMI, XM2 and XM3 to a common supply wire 104. The remainingterminal of transformer secondary winding 103 is connected through afuse 105 and a normally closed stop switch SW5 to the stationary contact1106 of a two position selector switch SW4 having a pole ll)? which maybe moved either to a first position bridging contacts 106 and d or asecond position bridging contact 109 and Jill). The stationary contact1% is connected to stationary contact Hit.

A wire llllll, associated with the various switches for providing manualoperation of the elements of the machine, is connected to the stationarycontact 1W9. When switch SW4 is placed in its manuaP position; namely,with the pole 107 in a dotted view position thereof shown in FlG; 8a,the wire 1111 is connected to the secondary 1030f transformer i102, andthe various operating components may be independently controlled throughrespective individual energizing circuits connected to wires 1111 and1104 through respective manually operable control switches. Thus, theforward and reverse coils MllF and MllR of the elevator motor Ml may beindependently controlled by employing a conventional reversing switchfor selectively connecting these coils between the wires 111i and lltldso as to provide operation of the elevator member 6d in a desireddirection. Likewise, the forward and reverse actuating coils MZF aNd MZRof the feeder motor M2 may be selectively controlled by a manuallyoperated reversing switch in the same manner; namely, by providing ameans for selectively connecting these coils between the wires lllll and104, as desired. This provides manual control of both the elevator motorM1 and the feeder motor M2. In the same manner operated selectorswitches may be provided on a controlpanel 112 for energizing therespective timers employed to control the energization of the solenoidsof the respective press pilot valve 48 associated with each of the pairsof pressure pods 35,35 of the respective platen press as semblies. Thus,manuallyoperated energizing switches may be employed to selectivelyenergize the solenoids of the pilot valves 4b to provide a timed presscycle. The manually controlled energizing circuits are not illustratedherein, since it is believed that these circuits are in themselves quiteconventional and would be well known to anyone skilled in the art. I

As will be presently described, the timers which are employed to controlthe duration of energization of the solenoids of the press pilot valves48 are of a type which includes a signal lamp 128 which becomesenergized simultaneously with the energization of the timer as it beginsits timed period of operation. The timer MT employed in each platenpress assembly is of a commercial type and may be similar to Model No.125 manufactured by Eagle Signal Company, Inc., Baraboo, Wisconsin.

FIGS. ha and db, taken together, represent the typical circuitarrangement required to operate one of the platen press assembliesautomatially, for example, the uppermost left end platen press assemblyof the 2d unit machine shown in FIG. l. The control circuits for theother platen press assemblies are substantially identical to thatillustrated in FIGS. 8a and 3b and are interconnected with the maincomponents of the system in the same manner as illustrated in thesefigures. Thus, the uppermost left end press assembly in the machine ofFIG. I is identified by the reference numeral 1A, and in the circuitdescription certain elements will be referred to this identifyingsymbol, while other elements in the circuit will be referred tocorresponding identifying symbols relating to elements controlled byportions of the circuit components of other press assemblies of themachine so as to provide required interlocks. Thus, a relay R1 isprovided, this relay being associated with the uppermost level of platenpress assemblies. A corresponding relay R2 is associated with the nextsubjacent level, etc., the relay for the lowest level being identifiedby R3. in the over-all system, alphabetical designations are employed todistinguish between different vertical rows of platen press assemblies;for example, A, B, C andD, reading from left to right in FIG. 1, andnumerical indicia are used to distinguish between different levelsproceeding downwardly from the uppermost level. For example, FIG. llillustrates a mold box 33 being pushed into the platen press assembly41); namely, the fourth platen press assembly from the top at the rightend of the machine, as viewed in FIG. 1.

. Certain portions of the circuit of FIGS. 8a and 8b are common to allthe other platen press assembly circuits. For example, the vacuum switchSW6, connected in the manner shown in FIG. 8b will afiect the circuitsof the other platen press assemblies in the same manner as it affectsthe circuit of the platen press assembly 1A. The same is true withrespect to the relay shown at R6, and the elements thereabove, includingthe enable switch SW3, the automatic-manual selector switch SW4 and thestop switch SW5.

With the switch SW il in the full line position thereof shown in FIG.8a; namely, with its pole 107' bridging the stationary contacts 106 andN8, it will be seen that the enable relay 7 R6 becomes energized whenthe enable switch SW3 is operated toits dotted view position, and relayR6 will be held energized by the closure of its holding contacts R6,.With all the elements in normal positions; namely, with no mold boxes inthe platen press assemblies, this will illuminate all of the push buttonswitches, which are of a type provided with illumination lamps 129, thelamps 1129 being connected in the manner illustrated in MG. 3a. Thus,the lamp 129 associated with switch SWllA has one terminal thereofconnected to wire W4 and has its other terminal connected by a wire ll13 to a stationary contact 3 of the associated timer MT. The contact 3is connected by a wire lid to a wire 1115, which is in turn connected toa stationary contact 7 of timer MT, normally engaged by a pole llllb ofthe timer switch assembly, said pole having a terminal 6. Terminal 6 isconnected by a wire 117 to a wire 118 which is connected to a stationarycontact 1.19 of the push button switch SW TA. Contact 1119 is connectedthrough the contact R6 of relay R6 to a wire 120 which is connected toone of the contacts 121 of switch SW3, which in turn is connected tostationary contact W8 of the selector switch SWd. Therefore, lamp 129becomes energized with the closure of the relay contacts R6 and remainsenergized until timer switch pole lilo disengages from contact 7.

It will be understood that in the normal starting condition of thepress, the elevator member 60 is in its intermediate position; namely,at a position aligned with the third or middle horizontal row of platenpress assemblies. As above explained, in this position the elevatormember 6% is flush with the conveyor leading from the mold box-fillingstation, and therefore can receive a filled mold box therefrom. Assumingthat the mold box is to be processed in platen press assembly 1A, theoperator moves the filled mold box leftward on the elevator member 6duntil it is aligned with the first vertical row of platen pressassemblies; namely, that containing the platen press assembly 1A. Withthe mold box in this position, the operator then actuates theilluminated push button switch SW1A. Switch SWlA is of the two pole typeand has a first pole 122 bridgingly engageable with a pair of stationarycontacts 119 and 123, and a second pole 124 bridgingly engageable with apair of stationary contacts 125 and 126. When pole 122 bridges contacts119 and 123, a platen relay RlA becomes energized, since the winding ofthis relay has one terminal thereof connected to wire 104 and the otherterminal thereof connected by a wire 127 to contact 123. Relay R1A isheld closed through a holding circuit including its contacts R1A RlA andR1A which connect wire 127 to switch contact 119. Relay contacts RlA areof the normally closed time opening type providing a time delay inopening after relay RIA becomes energized. The relay R1 for the firstelevation is likewise energized by the actuation of switch SW1A, sincethe winding of this relay has one terminal thereof connected to supplywire 104 and the other terminal thereof connected by a wire 130 throughnormally closed timed-opening contacts R1, of this relay to the switchcontact 126. As shown in FIG. 8a, the opposite stationary switch contact125 is connected to the wire 118, which is in turn connected throughcontacts R6 to switch contact 108, as above described. Relay Rl-is heldenergized for a period of time since the contacts R1 are of the timedopening type.

Energization of the relay R1 causes its contacts R1 (FIG. 8b) to close,which energizes the forward-driving motor coil MlF of the elevator motorM1 through a circuit including normally closed reverse coil interlockedcontacts M1 the normally closed contacts RM 1,, of a motor-starter relayRMl, a wire 131, a set of normally closed limit switch contacts 132, andthe relay contacts R1 From FIG. 8b it will be seen that the motordriving coil MlF is connected in this branch circuit between the powersupply wires 104 and 118. The limit switch contacts 132 are normallyclosed and are part of a limit switch assembly LS1 having a second pairof contacts 133 which are normally open as shown in FIG. 8b. The limitswitch LS1 is mounted on the frame of the machine in a position so thatit becomes actuated by the elevator member 60 when the elevator reachesthe uppermost level of platen press assemblies; namely, that containingthe selected platen press assembly 1A.

As shown in FIG. 8b, the reverse motor driving coil MIR, for loweringthe elevator assembly 60, has an en- -ergizing circuit connected betweenwires 118 and 104 which includes normally closed interlocked switchcontacts Mlp which open when the forward motor driving coil MlF becomesenergized. This energizing circuit also includes in series connectionnormally closed contacts RMl of the starter relay RM], normally closedinterlock relay contacts R R4 R2 and R1 and a normally closed limitswitch LS located on the main frame of the machine in a position suchthat it is held open when the elevator member 60 is in its normal homeposition; namely, at the intermediate, or third, level of platen pressassemblies.

The energization of the elevating coil MlF, by the circuit abovedescribed, causes the elevator member 60 to move upwardly, allowinglimit switch LS4 to close, but the energizing circuit for reversedriving coil MIR remains open because contacts R1, of relay R1 are heldopen at this time.

When the elevator member 60 reaches its intended height, namely, thelevel of the selected platen press assembly 1A, it operates the limitswhich LS1, opening the contacts 132 and closing the contacts 133.

The opening of the contacts 132 de-energizes the forward motor drivingcoil MlF, causing the motor to stop and causing the elevator to stop atthe intended level; namely, that corresponding to the platen pressassembly 1A.

. The vacuum responsive switch SW6 has a first set of normally opencontacts 134 which close responsive to a predeterminded degree of vacuumin the vacuum line 45. This degree of vacuum must be sufficient to causethe pods 35,35 of the selected platen press assembly to contract andelevate their associated platen member 36 sufficiently to permit theinsertion of a mold box therebeneath. The vacuum responsive switch SW6has another set of contacts 135 connected in the energizing circuit ofthe vacuum pump motor M3, the contacts 135 closing when the vacuum fallsbelow a limiting level, so that the motor M3 is energized sufficientlyto maintain the required degree of vacuum in the line 45.

Thus, with the required vacuum in line 45, when limit switch LS1 isactuated, closing its contacts 133, a relay RFS becomes energized. Asshown in FIG. 8b, the winding of the relay RFS is connected betweensupply wire 104 and wire 118 through the normally closed contacts RFl ofa forward feeder control relay RFl, the normally closed contacts 136 ofa limit switch LS2, the vacuum switch contacts 134, the contacts 133 oflimit switch LS1, the relay contacts RIA, of relay RlA, the wire 115,timer contact 7, timer swith pole 116, timer terminal 6, and wire 117.This energizes the relay RFS. This relay has a set of slow closingcontacts RFS connected between a wire 137 and one terminal of theforward driving coil M2F of the feeder motor M2. As shown in FIG. 8b,the wire 137 is the same as that connected to one terminal of relay RFSin the branch circuit above described. Thus, after the time periodrequired to close contacts RPS, the forward driving motor coil MZFbecomes energized in parallel with the winding of the relay RFS.

The elevator member 60 is provided with a limit switch LS3 which isnormally engaged by the feeder mechanism, for example, the carriagemember 77 so as to maintain the first set of its contacts 138 open and asecond set of its contacts 139 closed. When the motor M2 becomesenergized in the manner above described, the feeder mechanism isactuated so as to move the carria'ge member 77 and associated partsinwardly; namely, rightwardly as viewed in FIG. 3, which releases thelimit switch LS3.

It will be noted that a relay RE has its winding connected between wires104 and 118 through the limit switch contacts 139. When limit switchcontacts 139 open responsive to the inward movement of the feedercarriage assembly, relay RE becomes de-energized. Relay RE has a set ofcontacts RE,, and therefore these contacts close when relay RE becomesde-energized. It will be noted from FIG. 8a that the contacts RE are inshunt with the timed-opening contacts Rl in the holding circuit of therelay R1. Thus, relay R1 continues to be energized during this phase ofoperation.

The contacts 138 of limit switch LS close but do not have any effect atthis point.

The feeder mechanism reaches the end of its stroke wherein the mold box98 is pushed into the press space beneath the associated platen member36. The elevator member is provided with the limit switch LS2 located soas to be operated by the carriage assembly as it reaches the end of itsstroke. Limit switch LS2 has respective sets of contacts 140 and 136, asshown in FIG. 8b, the contacts 136 being normally closed and thecontacts 141) being normally open. When the feeder mechanism reaches theend of its inward stroke, the contacts 136 open and the contacts 1410close. The relay RFS becomes ole-energized, opening its contacts RF5,,thereby de-energizing the forward motor drive coil M2F. This causes thefeeder to stop its operation at this point. Thus, the contacts RPS, areof the slow closing type, so that there is a short time delay afterrelay RFS becomes energized before the motor coil MZ becomes energized,but these contacts open immegiately responsive to the de-energization ofrelay RF The closure of the contacts 149 of limit switch LS2 energizes arelay RF2 whose winding is connected between wire IM and wire 118through the limit switch contacts 140, as shown in FIG. 8b.

The timer operating coil, shown at 141 in FIG. @ahas one terminalthereof connected to supply wire 11M and the other terminal thereofconnected to timer terminal 1, which is in turn connected throughnormally open contacts RF2, of relay RF2 and through contacts R1A ofrelay R1A to the switch stationary contact 119, and hence to supply wire118. Hence, the closure of relay contacts RF2, causes the timer winding141 to become energized and to initiate a timer cycle.

Since the contacts 138 of limit switch LS are closed when the feedercarriage member 77 moves inwardly, the energization of the relay RFZ atthe end of the inward feeding stroke causes its contacts RF2 to closeand to energize a relay R1 1 which is connected between wire 101 and 118through said relay contacts and the limit switch contacts 139. A pair ofholding contacts RF1, of relay RF1 also close, these contacts beingconnected across the relay contacts RF2 as shown in FIG. 3b, therebyholding relay RFll energized. A short time thereafter, the timercontacts 6 and 3 are bridged by. the timer switch pole 116, causing thesolenoid 81A of the associated press pilot valve to be energized, sincethis connects said solenoid, shown at 81A inFlG. 8a, between wire 104.and wire 117. Similarly, the timer contacts 9 and 10 are bridged byanother pole 112 of the timer switch assembly, which establishes aholding circuit for the timer winding 141 through the closed timercontacts 11 and 12 which, as shown in FIG. 8a are at this time bridgedby a switch pole 143 of the timer switch assembly. Thus, with pole 142in engagement with contact 19, the holding circuit for the timer winding1 11 will comprise wire 11M, a wire 114, the timer winding 141, thetimer terminal 1, a wire 1 16 connected to the timer stationary switchcontact 12,

pole M3, a wire 1147, switch contact 111, the pole 142, the timerterminal 9, and wire 117, which is connected to the other supply wire11%. The energization of the solenoid of press pilot valve SlA causesthe associated pod elements 35,35 to become inflated, in the mannerabove described, and thereby causes the platen member 36 to movedownwardly and exert pressure on the mold box. As will be apparent fromFIG. 3b, the energization of the relay RF1 de-energizes the forwarddriving coil MZF of the feeder motor M2 by the opening of the relaycontacts RFL. The relay RF1 has a set of slow closing contacts RF1,which are connected in series with the reverse driving coil M2R'in acircuit between wire 11% and limit switch contacts 133, so that after ashort period of time subsequent to energization of relay R1 1, thereverse driving coil MZR ot the feeder motor M2 becomes energ'zed andstarts the feeder carriage member '77 back toward its home" position.This releases limit switch LS2, causing contacts Mil to open and 13b toclose, thereby de-energzing relay R1 2, but no other change takes placein the system at this point since the relay RE remains de-energized, itscontacts Re, remaining closed and thereby maintaining relay R1energized. Relay contacts RF2 open due to the deenergization of relayRFZ, but relay RF1 is held energized through its holding contacts RF1,and contacts 133 of limit switch LS3. The closure of limit switchcontacts 136 does not efl'ect any change since at this point thecontacts RlF1, of relay RFI remain open.

The feeder carriage member 77 eventually returns to its leftward, orstarting, position and trips limit switch LS3, closing the contacts 139and opening the contacts 133. The closure of the contacts 139 energizesrelay RE whose winding is connected between wires 11141 and 113 throughthe limit switch contacts 139, as shown in FIG. 8b. This de-energizesthe relay R1, since its holding circuit is opened by the opening of thecontacts RE, of the relay RE, as shown in FIG. 8a. It will be seen fromthis figure that the holding circuit for the relay R1 comprisesparallel-connected sets of relay contacts R1 and RE,, together with aset of relay contacts R1, of the relay R1. The relay contacts R1 shownin FIG. 8a are of the timed opening type, so that after the relay R1becomes energized, the contacts R1 open after a short time period, sothat the resultant holding circuit then consists of the contacts RE, andthe contacts R1, in series. Thus, the opening of the relay contacts RE,opens this holding circuit, causing relay R1 to drop out when limitswitchLS3 is tripped as above described.

The opening of the contacts 133 of limit switch LS3 tie-energizes therelay R1 1, causing its contacts RF1 to open and thereby de-energize thereverse driving coil MZR of the feeder motor M2. The feeder motor thusstops leaving the carriage member 77 in its normal starting position, asshown in full line view in FIG. 3.

The de-energization of the relay R1 at this point causes its'contacts R1as shown in FlG. 8b to close. Since at this time the elevator member 69is away from its normal position, the contacts of the limit switch LS4are closed,; namely, in the dotted position thereof shown in FIG. 3b, sothat the energizing circuit for the reverse driving coil M1R of theelevator motor becomes completed, through the closed interlock contactsMllp, RM1 R5,, R4,, and R2,. Elevator 60 then begins to descend,releasing limit switch LS1, causing its contacts 133 to open and itscontacts 132 to close. However, no other change in the system occurs atthis point, since contacts R1,, of relay R1 are open. The opening of thelimit switch contacts 133 likewise causes no further change in thesystem at this point, since the contacts RF5, of the relay RPS arelikewise open. When elevator 61) reaches its normal position; namely,its intermediate position above described wherein it is at the thirdlevel of the assembly, it trips limit switch LS4, causing it to open andthereby tie-energizing the reverse driving coil M1R of the elevatormotor M1, causing the elevator to stop in this position. The relay RlAhas a timed-opening set of contacts 121A, which times out after a periodof energization of relay RlA sufficiently long to allow the abovedescribed events, so that the relay RlA then drops out, allowing itsother holding circuit contacts RIA, and RlA as shown in FIG. 8a, toopen, and also allowing another set of contacts thereof R1A.,, connectedbetween wire 115 and contacts 133 of limit switch LS1 to open.

After a preset time interval, timer contacts 11 and 12 open by thedisengagement of pole 143 from contacts 12, causing the timer to bereset. Pole 116 separates from contact 8, thereby opening contacts 6-8,thus deenergizing the solenoid 81A of the associated press pilot valve,allowing its main valve 44 to return to its normal position, as shown inFIG. 7, wherein the pods 35,35 are reconnected to the vacuum line 45.This releases the pressure on the mold box and elevates the associatedplaten member 36 therefrom. Shortly before this time, pole l 16 engagescontact 7, bridging the contact 6 and 7 and energizing the signal lamp129 associated with the corresponding push button switch SWlA. Thus,this switch which is located on the panel assembly 101, becomesilluminated shortly before the end of the above described cycle,indicating that the mold box press unit 1A is available to receiveanother mold box to be processed in the machine. I

As previously described, when a mold box is inserted by the action ofthe feeder assembly, above described, the previously processed mold boxis pushed outwardly onto the rear portion of the elevator member beingengaged by a roller member 94 in the manner above described, to move themold box 98 onto the roller elements 68 and rearwardly into engagementwith the stop strip 73. The ejected mold box may then be manually movedonwardly on the receiving conveyor for demolding and further processing.

As abovementioned, the illuminated switches on the control panelassembly 101 inform the operator as to the correct positions to placemold boxes to be processed on the elevator member 60. Thus, theilluminated switches represent the respective available molding spacesin the machine and the operator places a mold box to be processed inalignment with a vertical row of spaces corresponding to that of anilluminated switch on board 101, which will thereafter be operated toautomatically insert the mold box into the indicated processing space.The timer may be so arranged as to illuminate the signal lamp 129 ashort time prior to the preset press time required; for example, theamount of prior time allowed may be about two seconds more than thelength of time required for the elevator to move the mold box to itsintended insertion position. When the operator pushes the start button,such as the operating button of the switch SWlA, as above described, theabove cyce of events takes place, the associated signal lamp 129becoming de-energized when the platen timer coil 141 becomes energized,initiating the timer cycle. This occurs when pole 116 disengages fromcontact 7, disconnecting wire 114 from wire 117, as above described. Aspreviously mentioned, each timer is provided with another signal lamp128 connected in parallel with its operating coil 141, and becomingenergizing simultaneously with the energization of said operating coil.

From the above description, it will be seen that when the machine isplaced in the "automatic" mode of operation, by operating the switch SW4to the position thereof shown in full line view in FIG. 8a, allmovements are automatic except for the placement by the operator of themold box in alignment with the vertical row of platen press assembliescontaining the one in which the mold box is to be inserted. Theoperation of the elevator and feeder members is quite rapid, and in atypical embodiment of the invention, the maximum time that the elevatormember 60 is away its home" position was about 15 seconds.

As will be readily understood, when the mold box is to placed at levelsbelow the home" position of the elevator member 60; for example, at thefourth of fifth level from the top, the response of the motor M1 whichdrives the elevator must be reversed as compared with that describedabove in connection with the placement of a mold box in the platen pressspace 1A. Thus, a reversing relay RMl (see FIG. 8b) is provided whichresponds to the operation of any of the push buttons associated with thefourth or fifth levels. Thus, the winding of the relay RMl is connectedin an energizing circuit which includes parallel-connecting contacts ofrelays in the control circuits for the fourth and fifth level platenpress assemblies corresponding to the relay RlA shown in FIG. 8a. Thus,operation of a push button associated with the fourth or fifthhorizontal row of platen assemblies energizes a relay similar to therelay RlA, and closure of one of its contacts completes the energizingcircuit for the relay RM]. and energizes same. As shown in FIG. 8b, thedriving coils MlF and MlR have normal energizing circuits respectivelycontaining normally closed contacts RMI, and RM1 of the relay RMl. Thus,energization of the relay opens these normal energizing circuits.Reversing connections are provided for energizing the drive coils MlFand MIR through respective reversing branch connections indicatedrespectively at 162 and 163. The reversing branch 162 contains a set ofnormally open contacts RMl of the relay RM1 which close responsive tothe energization of relay RMl and thereby allow energization of thereverse drive coil M1R from the conductor 131 in place of the forwarddrive coil MlF. Similarly, the energization of the relay RMl closes aset of normally closed contacts RM1 of relay RMl connected in thereversing branch connection 163, allowing energization of the forwarddrive coil M1F in place of the reverse drive coil MIR. Thus,energization of relay RM1 provides a reversal of the connections foroperating the motor drive coils MlF and M1R, required for moving theelevator member 60 to the fourth and fifth levels instead of to thefirst and second levels of platen press assemblies.

It will also be noted from FIG. 8b that the energizing circuits for thedriving coils MlF and MIR contain respective normally closed interlockswitch contacts shown at M1,, and MI Contacts M1,, open responsive tothe energization of the motor driving coil MIR thereby preventingenergization of the motor drive MlF at this time. Similarly, theenergization of the motor drive coil MIF opens the interlocked switchcontacts M1,, preventing energization of motor drive coil MIR. Theseinterlocking sets of switch contacts prevent simultaneous energizationof both motor drive coils. Similarly, the interlocking contact R1,, R2,,R4,, and R5, are normally closed and are connected in the energizingcircuit for the motor driving coil which is energized to return theelevator member 60 to its home position, along with the limit switchLS4. These interlocked switch contacts open responsive to theenergization of the relays corresponding to the relay R1 associated withthe platen press assemblies of the first, second, fourth, and fifthlevels. As shown in FIG. ha, the relay R1 becomes energized responsiveto the bridging of contacts 125 and 126 by the pole 154 when the switchSWllA is operated. Thus, the interlocked contacts R1 R2,, R5 prevent anyreturn movement of the elevator member 60 when any of the relays for thefirst, second, fourth and fifth levels is energized.

While the multiple molding press of the present invention has been abovedescribed specifically for handling mold boxes employed with foamingplastic materials, it is readily apparent that the press of the presentinvention can have application for other types of work pieces, such asvarious types of laminated glued wood objects including laminated tabletops, cabinet walls, top panels, or the like. These parts may be carriedon a board, or similar plate-like support into position in the press.The press system of the present invention is also applicable to othergluing operations where; for example, two or more flat panels arestacked, freshly glued, ready for pressing.

While a specific embodiment of an improved multiple molding pressassembly has been disclosed in the foregoingdescription, it will beunderstood that various modifications within the spirit of the inventionmay occur to those skilled in the art. Therefore, it is intended that nolimitations be placed onthe invention except as defined by the scope ofthe appended claims.

' WHAT IS CLAIMED IS:

l. A multiple molding press assembly comprising upstanding frame means,a plurality of vertically spaced fixed horizontal work piece supportelements on said frame means, respective horizontal platen membersmounted on said frame means over said support elements, meansto'independently reciprocate said platen 2. The multiple molding pressassembly of claim l,

and wherein the means to reciprocate said platen member comprisesrespective fluid pressure-operated driving members connected between theplaten members and said frame means. r

3. The multiple molding press assembly of claim 2,

sources, and means for selectively connecting said positive and negativepressure fluid sources to said fluid pressure-operated driving members.

41. The multiple molding press assembly. of claim 3, and wherein saiddriving members comprise flexible bellows members connected between theplaten members and upwardly adjacent portions of said frame means.

5. The multiple molding press assembly of claim 41, and means normallyconnecting the bellow members to said negative pressure fluid source,said means for selectively connecting the sources to the bellows mem-'55 and respective positive andnegative pressure fluid bers comprisingreversing valve means interconnecting the bellows members with saidpressure fluid sources.

6. The multiple molding press assembly of claim 5, and wherein saidreversing valve means comprises respective main fluid pressure-operatedvalves connected between the fluid pressure sources and said bellowsmembers and having ports normally connecting said negativefluid pressuresource to said bellows members and other ports connecting the positivefluid pressure source to the bellows members responsive to operatingfluid pressure applied to the main valves, and independently controlledpilot valve means operatively connected between the positive fluidpressure source and the main valves.

7. The multiple molding press assembly of claim 6, and wherein saidpilot valve means comprise respective valves having operating solenoids,and means to selectively energize said solenoids.

8. The multiple molding press assembly of claim 7, and means to preventenergization of a selected solenoid unless the vertically movable workpiece receiving member is at a level substantially registeringwith thecorresponding work piece support element.

9. The multiple molding press assembly of claim ll, and transverselymovable work piece-engageable feeder means on the front portion of thework piece receiving member. I

, 110. The multiple molding press assembly of claim 9, and means toactuate said feeder means responsive to the positioning of said workpiece receiving member at a selected position of registry with ahorizontal work piece support element.

11. The multiple molding press assembly of claim 10, and means to moveeach platen member downwardly to press position responsive to actuationof said feeder means through a feeding stroke substantially sufficientto move a work piece beneath the platen member.

12. The multiple molding press assembly of claim 1 l, and means tomaintain downward press force on the platen member for a timed periodand to thereafter release the platen member.

13. The multiple molding press assembly of claim 12, and wherein saidmeans to move each platen member downwardly to press position comprisesan expansible bellows member connected between the platen member and anupwardly adjacent portion of said frame means, and means to admitpressure fluid into said bellows member responsive to the actuation ofsaid feeder means through said feeding stroke.

14. The multiple molding press assembly of claim 13, and means to returnsaid feeder means on said work piece receiving member after said feedermeans reaches the end of said feeding stroke.

15. The multiple molding press assembly of claim 14, and wherein saidwork piece receiving member has a normal home position, and means toreturn said work piece receiving member to said home position at the endof the retraction stroke of said feeder means.

116. The multiple molding press assembly of claim 15, and wherein saidnormal home position of said workpiece receiving member is substantiallyin registry with one of said horizontal work piece support elements.

117. The multiple molding press assembly of claim 16, andwherein atleast three vertically spaced fixed horizontal work piece supportelements are provided and said normal home.position is in registry withan intermediate work piece support element.

18. The multiple molding press assembly of claim 1, and wherein themeans to move said work piece receiving member vertically on said framemeans comprises vertical screw means on said frame means and threadedlyengaged with said work piece receiving member, and means to rotate saidvertical screw means.

19. The multiple molding press assembly of claim 18, and wherein saidscrewmeans is journaled on said frame means and said means to rotatesaid vertical screw means comprises a reversible electric motor andmeans drivingly coupling said electric motor to said vertical screwmeans.

20. The multiple molding press assembly of claim 1, and transverselymovable workpiece-engageable feeder means on the front portion of theworkpiece receiving member, and wherein said transversely movable feedermeans comprises transverse guide rail means on said workpiece receivingmember, a workpiece engaging abutment member slidably mounted on saidrail means, and drive means connected to said abutment member.

21. The multiple molding press assembly of claim 20, and wherein saidlast-named drive means comprises a reversible electric motor mounted onsaid workpiece receiving member, and means drivingly connecting saidlast-named electric motor to said abutment member.

22. The multiple molding press assembly of claim 20, and horizontaldrive roller means longitudinally journaled on said rear portion of saidworkpiece receiving member for drivingly engaging a workpiece ejectedrearwardly from beneath a platen member, and means drivingly couplingsaid roller means to said abutment member for actuation simultaneouslytherewith.

23. The multiple molding press assembly of claim 1, and wherein themeans to reciprocate said platen members comprises respective fluidpressure-operated driving members connected between the platen membersand said frame means, respective positive and negative pressure fluidsources, means for selectively connecting said positive and negativepressure fluid sources to said fluid pressure-operated driving members,and means to maintain the pressure of said negative pressure fluidsource between predetermined limits.

24. The multiple molding press assembly of claim 23, and wherein saidnegative pressure fluid source comprises a vacuum pump and a drive motoroperatively connected to said pump, said last-named motor having anenergizing circuit including a pressure-responsive switch connected soas to respond to the output pressure of said vacuum pump, said switchhaving auxiliary contacts, transversely movable workpiece-engageablefeeder means on the front portion of the workpiece receiving member, andmeans to inhibit action of said feeder means unless said auxiliarycontacts are closed.

25. The multiple molding press assembly of claim 1, and transverselymovable workpiece-engageable feeder means on the front portion of theworkpiece receiving member, means to actuate said feeder meansresponsive to the positioning of said workpiece receiving member at aselected position of registry with a horizontal workpiece supportelement, means to move each platen member downwardly to press positionresponsive to actuation of said feeder means through a feeding strokesubstantially sufficient to move a workpiece beneath the platen member,means to maintain downward press force on the platen member for a timedpe riod and to thereafter release the platen member, indicator means,and means to energize said indicator means a short time prior to the endof said timed period, whereby said workpiece receiving member may bestarted toward said selected position of registry with the horizontalworkpiece support element.

26. A multiple molding press assembly comprising a support, a pluralityof vertically spaced independently operable press units on said support,means to selectively operate said press units, a workpiece elevatoradjacent said support adapted to receive a workpiece for pressureprocessing, means to selectively move said elevator vertically intoregistry with said press units, and means on the elevator to move aworkpiece horizontally into a press unit when it is in registry withsaid press unit.

1. A multiple molding press assembly comprising upstanding frame means,a plurality of vertically spaced fixed horizontal work piece supportelements on said frame means, respective horizontal platen membersmounted on said frame means over said support elements, means toindependently reciprocate said platen members, a horizontal work piecereceiving member engaged on said frame means and being verticallymovable thereon, said work piece receiving member having a horizontalfront portion registrable with a selected horizontal work piece supportelement for feeding a work piece thereto for pressure processing and ahorizontal rear portion simultaneously registering with the work piecesupport element for receiving a processed work piece therefrom, andmeans to selectively move the work piece receiving member vertically onsaid frame means to positions of registry with said horizontal workpiece support elements.
 2. The multiple molding press assembly of claim1, and wherein the means to reciprocate said platen member comprisesrespective fluid pressure-operated driving members connected between theplaten members and said frame means.
 3. The multiple molding pressassembly of claim 2, and respective positive and negative pressure fluidsources, and means for selectively connecting said positive and negativepressure fluid sources to said fluid pressure-operated driving members.4. The multiple molding press assembly of claim 3, and wherein saiddriving members comprise flexible bellows members connected between theplaten members and upwardly adjacent portions of said frame means. 5.The multiple molding press assembly of claim 4, and means normallyconnecting the bellow members to said negative pressure fluid source,said means for selectively connecting the sources to the bellows memberscomprising reversing valve means interconnecting the bellows memberswith said pressure fluid sources.
 6. The multiple molding press assemblyof claim 5, and wherein said reversing valve means comprises respectivemain fluid pressure-operated valves connected between the fluid pressuresources and said bellows members and having ports normally connectingsaid negative fluid pressure source to said bellows members and otherports connecting the positive fluid pressure source to the bellowsmembers responsive to operating fluid pressure applied to the mainvalves, and independently controlled pilot valve means operativelyconnected between the positive fluid pressure source and the mainvalves.
 7. The multiple molding press assembly of claim 6, and whereinsaid pilot valve means comprise respective valves having operatingsolenoids, and means to selectively energize said solenoids.
 8. Themultiple molding press assembly of claim 7, and means to preventenergization of a selected solenoid unless the vertically movable workpiece receiving member is at a level substantially registering with thecorresponding work piece support element.
 9. The multiple molding pressassembly of claim 1, and transversely movable work piece-engageablefeeder means on the front portion of the worK piece receiving member.10. The multiple molding press assembly of claim 9, and means to actuatesaid feeder means responsive to the positioning of said work piecereceiving member at a selected position of registry with a horizontalwork piece support element.
 11. The multiple molding press assembly ofclaim 10, and means to move each platen member downwardly to pressposition responsive to actuation of said feeder means through a feedingstroke substantially sufficient to move a work piece beneath the platenmember.
 12. The multiple molding press assembly of claim 11, and meansto maintain downward press force on the platen member for a timed periodand to thereafter release the platen member.
 13. The multiple moldingpress assembly of claim 12, and wherein said means to move each platenmember downwardly to press position comprises an expansible bellowsmember connected between the platen member and an upwardly adjacentportion of said frame means, and means to admit pressure fluid into saidbellows member responsive to the actuation of said feeder means throughsaid feeding stroke.
 14. The multiple molding press assembly of claim13, and means to return said feeder means on said work piece receivingmember after said feeder means reaches the end of said feeding stroke.15. The multiple molding press assembly of claim 14, and wherein saidwork piece receiving member has a normal ''''home'''' position, andmeans to return said work piece receiving member to said ''''home''''position at the end of the retraction stroke of said feeder means. 16.The multiple molding press assembly of claim 15, and wherein said normal''''home'''' position of said work piece receiving member issubstantially in registry with one of said horizontal work piece supportelements.
 17. The multiple molding press assembly of claim 16, andwherein at least three vertically spaced fixed horizontal work piecesupport elements are provided and said normal ''''home'''' position isin registry with an intermediate work piece support element.
 18. Themultiple molding press assembly of claim 1, and wherein the means tomove said work piece receiving member vertically on said frame meanscomprises vertical screw means on said frame means and threadedlyengaged with said work piece receiving member, and means to rotate saidvertical screw means.
 19. The multiple molding press assembly of claim18, and wherein said screw means is journaled on said frame means andsaid means to rotate said vertical screw means comprises a reversibleelectric motor and means drivingly coupling said electric motor to saidvertical screw means.
 20. The multiple molding press assembly of claim1, and transversely movable workpiece-engageable feeder means on thefront portion of the workpiece receiving member, and wherein saidtransversely movable feeder means comprises transverse guide rail meanson said workpiece receiving member, a workpiece engaging abutment memberslidably mounted on said rail means, and drive means connected to saidabutment member.
 21. The multiple molding press assembly of claim 20,and wherein said last-named drive means comprises a reversible electricmotor mounted on said workpiece receiving member, and means drivinglyconnecting said last-named electric motor to said abutment member. 22.The multiple molding press assembly of claim 20, and horizontal driveroller means longitudinally journaled on said rear portion of saidworkpiece receiving member for drivingly engaging a workpiece ejectedrearwardly from beneath a platen member, and means drivingly couplingsaid roller means to said abutment member for actuation simultaneouslytherewith.
 23. The multiple molding press assembly of claim 1, andwherein the means to reciprocate said platen members comprisesrespective fluid pressure-operated driving members connected between theplaten members and said frame means, respective positive and negativepressure fluid sources, means for selectively conNecting said positiveand negative pressure fluid sources to said fluid pressure-operateddriving members, and means to maintain the pressure of said negativepressure fluid source between predetermined limits.
 24. The multiplemolding press assembly of claim 23, and wherein said negative pressurefluid source comprises a vacuum pump and a drive motor operativelyconnected to said pump, said last-named motor having an energizingcircuit including a pressure-responsive switch connected so as torespond to the output pressure of said vacuum pump, said switch havingauxiliary contacts, transversely movable workpiece-engageable feedermeans on the front portion of the workpiece receiving member, and meansto inhibit action of said feeder means unless said auxiliary contactsare closed.
 25. The multiple molding press assembly of claim 1, andtransversely movable workpiece-engageable feeder means on the frontportion of the workpiece receiving member, means to actuate said feedermeans responsive to the positioning of said workpiece receiving memberat a selected position of registry with a horizontal workpiece supportelement, means to move each platen member downwardly to press positionresponsive to actuation of said feeder means through a feeding strokesubstantially sufficient to move a workpiece beneath the platen member,means to maintain downward press force on the platen member for a timedperiod and to thereafter release the platen member, indicator means, andmeans to energize said indicator means a short time prior to the end ofsaid timed period, whereby said workpiece receiving member may bestarted toward said selected position of registry with the horizontalworkpiece support element.
 26. A multiple molding press assemblycomprising a support, a plurality of vertically spaced independentlyoperable press units on said support, means to selectively operate saidpress units, a workpiece elevator adjacent said support adapted toreceive a workpiece for pressure processing, means to selectively movesaid elevator vertically into registry with said press units, and meanson the elevator to move a workpiece horizontally into a press unit whenit is in registry with said press unit.